Model Example Of Cooperation

Nn Shipyard Works With Electric Boat On Mock-up Sub

Congress is still debating whether Newport News Shipbuilding and Electric Boat can team up to build Navy attack subs, but the once-bitter rivals already have one under way.

Sort of. It's just a model.

But while it's smaller than the real thing, at quarter-scale it's bigger than a breadbasket. It will take five flatbeds to get the pieces - some built in Connecticut, some in Virginia - out to Idaho's Lake Pend Oreille for final assembly and launching.

The unmanned, battery-powered Cutthroat, named for the red-throated trout indigenous to the lake, will be a $50 million guinea pig. As the Navy commissions its next class of subs - 30 boats to be built over the next 20 years - the Cutthroat will drive design changes inside and out.

The boat isn't the first quarter-scale model the Navy has used. The Kokanee, built in 1987, already roams Pend Oreille, which is up to 1,000 feet deep. At 91 feet long, though ,the Cutthroat will be the biggest.

More important, say project engineers, it's the first true replica and the most adaptable. In fact, the modular Cutthroat will start as a quarter-scale Seawolf, then a section will be added to the forward pressure hull to make it a 111-foot version of the new attack sub.

Shuffling pieces of a table-top Cutthroat, a model of the model, NNS' design manager for underwater vehicles, John A. Lamb, and EB principal engineer Pieter Van Dine say the project is miles ahead of the Kokanee.

The Navy used that model to test propulsion systems for the short-lived Seawolf program. The Cutthroat will do far more, they say.

Inside the boat, the builders will try out an electric-drive motor. On a real sub, the motor would be powered by a nuclear reactor rather than batteries, but it still should be quieter and more "power dense" then the nuclear-powered gearing system that today's subs use.

And the motor will have the latest electric rig, using "permanent magnet" technology rather than the "squirrel-cage induction" process of the past.

Say what? The particulars quickly drift into the classified or the boring, Van Dines says, but rest assured, no caged squirrels were ever involved. The point is, he says, the model will let the Navy try out a new propulsion system for millions of dollars less than it would cost to try it on a full-size sub - and without putting a sub and its crew at risk.

Outside the boat, NNS and EB will try out new coatings designed to let subs slip more quietly through the water. It's a test the Kokanee wasn't buoyant enough to handle because of the extra weight. Unlike the earlier model, the Cutthroat can pitch, roll and dive because it can be fitted with different sails whose positions shift from fore to aft.

And because the Cutthroat is a "geo-sim" - meaning it's shaped just like the Seawolf - and ultimately just like the new attack sub - changes that affect speed, handling and stealth can be clearly measured.

Flat-bottomed Pend Oreille, one of the country's deepest lakes, never freezes, providing a laboratory akin to a wind tunnel for testing airplane wings.

The noise of the ocean won't get in the way of acoustic data. And in the middle of government-owned parkland, the lake lends secrecy to a classified operation, Lamb adds.

A team of about 50 employees from NNS and EB started designing the Cutthroat in March. As construction begins, about 120 will be assigned to the project - not exactly a quarter-size work force. Just to design the first new attack sub, which will undergo construction at the same time as the model, EB has had 1,000 people on the job.

"It's not one of those scaling factors that works out," says Lamb.

The Cutthroat is scheduled to be delivered to the Navy in 2000, two years after construction starts on the first sub in the new class. What that means, say Lamb and Van Dine, is that experiments with the Cutthroat in the depths of the Pend Oreille likely will have little effect on the first few boats in the class.

"Quite frankly, you would have wanted this thing to get started two years ago," Lamb says. "But I think the court was out on just how effective quarter-scale testing could be."

According to Van Dine, the success of the NNS-built Kokanee is what convinced the Navy. He says that model should produce significant changes between the first Seawolf, delivered last week, and the third and final Seawolf, which won't be christened for at least another three years.

The need for that proof may have delayed the Cutthroat, but the model's influence on the new attack class will be felt, Lamb says, even if it takes a little longer than hoped. The Cutthroat is designed to last 20 years - the period over which the new class of subs will be built.

When the program reaches subs No. 7 and 8, he says, "I think you'll start to see revolutionary changes."

The Cutthroat is more than a submarine model. It's also a model for NNS-EB cooperation that goes beyond anything the two yards have done before.

When NNS and EB shared some design work on the Seawolf, Van Dine says, whenever he came to consult with NNS he was shuttled off to a corner so he couldn't see anything. Lamb laughs and says that's not the case anymore: "Now I walk in and Pieter's in my office."

Though the yards both designed the Seawolf, the Cutthroat is the first time they will have planned and built a boat together. And that's exactly what they are asking Congress to let them do for the entire new attack class. The Navy backs the partnership, but while some on Capitol Hill like the two-heads-are-better-than-one idea, others worry that less competition could drive up costs.

So in a program for 30 subs at $1.7 billion apiece, Lamb and Van Dine meet weekly with Rear Adm. J. Philip Davis, the Navy's head of sub technology, to talk about a model that represents only a fraction of the total cost. "A $50 million contract wouldn't normally get the attention this gets," Lamb says.